No. If the machine is off line when a document is sent,
it will have none of the information that was sent to it.
Said document needs to be re-sent. If you are expecting
an important document from someone and you think
that you might have missed it, it would be a good idea
to call that someone and find out if same was sent.
Usually, a fax machine will not send a document if your
fax machine is not on line. A working fax machine will
answer the line and send the correct signal(s) to the
machine that called to proceed with the transmission
of document(s).